Device to Device (D2D) communication indicates direct signal transmission and reception between terminals without passing through a base station. That is, the D2D communication allows the communication between the adjacent terminals using a standard or a resource allocated by the base station without passing the base station. The D2D communication is contrasted with cellular communication. The cellular communication includes communication between the base station and the terminal and is referred to as Device to Base Station (D2B) or Base Station to Device (B2D) communication.
FIG. 1 illustrates D2D communication in a cellular network according to the related art.
Referring to FIG. 1, a User Equipment 1 (UE1) 121 and a UE2 122 are paired for their D2D communication and concurrently connected to a Base Station (BS) 110. The UE1 121 and the UE2 122 paired for the D2D communication are connected to the BS 110 through a first D2B connection and a second D2B connection respectively, and concurrently establish the D2D connection between them. Hence, the UE1 121 and the UE2 122 can communicate with the BS 110 to use a service requiring an external network, and communicate with each other directly using the D2D connection to exchange data between them, rather than transmitting the data over the existing cellular network.
The single UE can hold both of the D2D connection and the D2B connection as shown in FIG. 1. In this case, the UE needs to process both of the D2D communication signal and the D2B communication signal. Further, the UE needs to process only the D2D signal in the D2D communication, and only the D2B signal in the D2B communication. In so doing, efficiency of current consumption and cost increase for the signal processing depends on configuration of a transmitter and a receiver for processing the D2D signal and the D2B signal.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.